The present invention relates to a support structure for use with an image processing apparatus. The apparatus includes an apparatus body, a base provided at a lower portion of the apparatus body for supporting the body, and an image processing unit disposed inside the apparatus body or attached thereto, the unit being capable of effecting at least either an image forming operation or an image reading operation. An example of the image processing apparatus of this type is a copier.
With an image processing apparatus of the above-noted type, in general, there are provided rubber supports in the form of short columns attached to the bottom of the apparatus body for supporting it. The present applicant previously proposed anchoring such rubber supports to the bottom with screws (e.g. Japanese utility model application “Kokai” No.: Hei. 06-10950).
Subsequent to the above, this applicant addressed the problem of flexion which occurs between the bottom portions supported by the respective rubber supports. Then, to overcome this problem, the applicant proposed providing a projection at an intermediate position where such flexion between the rubber supports is likely to occur (Japanese patent application “Kokai” No.: 2002-166621). Specifically, in one Example, the projection comprises a rigid hollow tubular member accommodating an elastic member therein. The elastic member is adapted to come into contact with the floor surface to support the apparatus body together with the rubber supports only when the apparatus body is moved downwardly in association with elastic deformation of the rubber supports. In this construction, the rubber supports are designed to come into contact with the floor surface before the elastic member comes into contact with the same. For this reason, under the non-grounded condition, the leading end of the elastic member is recessed (toward the apparatus body base) relative to the leading ends of the rubber supports.
When such rubber supports as above are employed, the rubber supports are usually provided at three or more positions on the bottom surface of the base. The use of the rubber material is for restricting slippage of the apparatus body even when it is mounted on a slippery surface such as a slippery floor or table surface while supporting the weight of the apparatus body. The use of the elastic material such as rubber provides another advantage of avoiding damage to material forming the other member or portion (e.g. the floor surface) to be placed in contact therewith.
However, if the support needed for the apparatus body relies solely on such rubber supports as above, it has been found that while the problem of slippage can be substantially solved, another problem tends to occur when they are used with a more recent type of image processing apparatus as will be detailed later.
Namely, when the rubber supports are employed, these supports, depending on the hardness of the material used therefor, will be compressively deformed in the vertical direction by the weight of the apparatus body. Such compressive deformation may not present any big problem in the case of an image processing apparatus not having an image reading function, such as a printer. Whereas, in the case of an image processing apparatus having the image reading function, in particular, a copier having a scanner, the optical reader unit or the scanner is mounted at a relatively upper portion of the apparatus body. Hence, the compressive deformation significantly affects the levelness and parallelism of the mounting surface for the optical unit located at such upper portion of the apparatus body. Accordingly, unless high precision is ensured in this respect, the optical reading unit per se will be physically distorted, thus resulting in distortion, impaired squareness of the image obtained thereby, etc.
In the case of more conventional apparatus, the center of gravity of the apparatus substantially coincides with the center of the apparatus body in plan view. In this case, its optical unit is not significantly affected. This is not the case with a more recent image processing apparatus which is referred to as “in-body discharge type” (wherein finished paper sheets or the like are discharged into a hollow space formed in the middle of the apparatus main body). This type of apparatus requires that a relatively heavy driving unit be mounted at a rear side of the apparatus body, in particular, with an offset toward its image fixing unit. The deviation of the gravity center in plan view results in non-negligible difference among the compressive deformation amounts of the rubber supports.
More particularly, in the case of such in-body discharge type apparatus, one rubber support located closest to the gravity center will be deformed by the greatest amount, whereas the other supports will not be compressed so largely. Hence, it has been found that the problem of the levelness and parallelism tends to occur conspicuously in the case of an apparatus having an apparatus body formed of a standard resin material.
This problem will be described in greater details with reference to a typical in-body discharge type apparatus. This apparatus has a total apparatus weight of 39 kg. The center of gravity is offset to the left rear side of the apparatus body. The apparatus body including its base is formed integrally of a resin material and rubber supports are arranged uniformly at four corners of the bottom face of the apparatus body.
The rubber supports are formed as rectangular columns (20×22×8.5 mm) made of ethylene propylene (EPDM) rubber having hardness of 60° as determined according to JIS (Japan Industrial Standard) K 6301 A. When attached to the bottom face of the apparatus, each support, under its uncompressed state (i.e. non-grounded condition), projects from the bottom surface of the apparatus body by 5 mm.
In use of the apparatus when mounted on a floor surface or the like, the rear left rubber support will be compressed by about 2 mm, while the rear right support and the front left support will be compressed by about 1 mm and the front right support will be compressed by about 0.5 mm. Because of these differences in the compression amounts, there occurs deviation from the levelness in the mounting surface for the optical reader unit corresponding to the differences.
On the other hand, if the apparatus body is supported directly on the mounting surface or the like without using the rubber supports attached thereto at the respective attaching positions thereof, both sufficient levelness and parallelism are ensured in the mounting surface for the optical unit.
With the prior art disclosed by Japanese patent application “Kokai” No.: 2002-166621 cited above, while it is possible to solve the problem of flexion between the supported positions of the base of the apparatus body, it is not possible to cope with the latter-mentioned problem of differing compression amounts among the respective rubber supports.
Further, for this type of rubber support, it is also important that the rubber support be not easily removed when a user drags the image processing apparatus body on the floor surface or lifts up the apparatus body therefrom after the body has been installed thereon for a long time. Namely, in order to ensure good use condition of the rubber supports for an extended period of time, it is required that the rubber supports be designed to effectively resist such inadvertent detachment thereof in case the apparatus body is dragged or lifted up after a long time installment.